243 vs 260 S.D. or Velocity rules?

[Mr Humble]

This question relates to Berger VLDs. I am being told that the highest BC 6mm Berger launched from a 243 Winchester will outrange, shoot flatter and be more accurate that the highest 6.5mm Berger (that has a higher BC) shot from a 260 Remington. Assume identical 26" barrel rifles with the proper twist for each bullet.
I thought BC ruled but am I wrong? Thanks.

 

[Armed in Utah]

Pic looks like a 695 Tikka ? In 6.5x55 ?

Run a comparison on a ballistics chart...Real Guns.com has an easy one.......I have both a 6XC (27" Pac Nor) & 260 AI (28" Pac Nor) w/8 twists...with my experience with both the 107 SMK 6mm @ 2925 & the 6.5mm 142 SMK (595 BC) also at 2925 fps....the 260 AI is gonna be flatter/longer...

 

[Mr Humble]

Thanks I thought a 6.5 would do better than a 243.

It is a Tikka 595 Super Sporter (replaced by the SAKO TRG). They were made in lots of neat calibers not imported. All that was were 223, 22-250 & 308.
In Europe there were 6.5x55, 7x64, 9.3x62 and probably more.
How I got mine is a complex tale, but I got it.

 

[Mikecr]

The caveat here resides in the fact that the 243/105 is potentially faster than a 260/140, given the same powder capacity. But not without a cost.
And at some range, the slower 140 would catch and pass the 105.

If you compared cartridges with similar capacity/bore ratios(producing same velocites) you would find the 140 leaving a 105 behind right from the git-go.
But neither could be declared more accurate.